/**  
         * 查找二叉树中的最大元素  
         *  
         * @className: FindMax  
         * @author: Max Solider  
         * @date: 2023-06-11 15:23  
         */public class FindMax {  

            public static BinaryTreeNode findMax(BinaryTreeNode root) {  
                if (root == null) {  
                    return null;  
                }  
                BinaryTreeNode max = root;  
                BinaryTreeNode leftMax = null;  
                BinaryTreeNode rightMax = null;  
                if (root.getLeft() != null) {  
                    leftMax = findMax(root.getLeft());  
                }  
                if (root.getRight() != null) {  
                    rightMax = findMax(root.getRight());  
                }  
                if (leftMax != null && max.getData() < leftMax.getData()) {  
                    max = leftMax;  
                }  
                if (rightMax != null && max.getData() < rightMax.getData()) {  
                    max = rightMax;  
                }  
                return max;  
            }  

            public static void main(String[] args) {  
                BinaryTreeNode node4 = new BinaryTreeNode(4, null, null);  
                BinaryTreeNode node5 = new BinaryTreeNode(5, null, null);  
                BinaryTreeNode node6 = new BinaryTreeNode(6, null, null);  
                BinaryTreeNode node7 = new BinaryTreeNode(7, null, null);  
                BinaryTreeNode node2 = new BinaryTreeNode(2, node4, node5);  
                BinaryTreeNode node3 = new BinaryTreeNode(3, node6, node7);  
                BinaryTreeNode node1 = new BinaryTreeNode(1, node2, node3);  
                System.out.println(findMax(node1).getData());  
            }  
        }